Mary made by Scott's, and the review (on their website no less) is low in stars. But, so is the review total for their Black Magic and I used that for mature container plants one year with no complaints, it stayed light, didn't compact, plants were happy.

Here is a link that might be useful: Earth Gro - Scotts

I used a bale of Promix this year but am wintersowing more than I anticipated so I got a bag of the Earth Gro and am mixing it with the Promix to make the Promix go further. It seems to be okay so far when mixed.